Subminiature coaxial contact

ABSTRACT

A subminiature coaxial contact is provided with a cavity in one end for receiving a center conductor of a small-size coaxial cable and has a dielectric sleeve movably positioned thereon being initially disposed intermediate the ends thereof. The contact is insertable into one end of a connector housing having a shoulder stop therein against which the dielectric sleeve registers so that upon continued insertion the dielectric sleeve is caused to slidably traverse the contact until it is positioned against the end of the coaxial cable insulating sheath. The dielectric sleeve thus may serve as a positioner or stop for use with a crimping tool so that crimping occurs on the extreme end of the contact whereby bending is at a minimum and also is operative to positively locate the contact in a predictably fixed position in the housing while simultaneously aligning the same diametrically in spaced relation within a small bore therein.

United States Patent 1 [111 3,757,278

Schumaeher Sept. 4, 1973 SUBMINIATURE COAXIAL CONTACT PrimaryExaminer-Marvin A. Champion [75] Inventor: William Ludlow Schumacher,Camp Assistant Exafniner Lawrence swab m p Attorney-William J. Keatinget 31., Gerald K. Kita,

John R. Flanagan and Allan B. Osborne [73] Assignee: AMP Incorporated,Harrisburg, Pa.

[22] Filed: Oct. 19, 1971 [57] ABSTRACT PP- 190,507 A subminiaturecoaxial contact is provided with a cavity in one end for receiving acenter conductor of a 52 us. Cl. 339/177 R, 29/629 small'siz? axialcable and has a dielectric Sleeve [51] Int. Cl H01! 17/06 ablxposltionedthereon being initially disposed inter; [58] Field of Search 29/629;174/75 c, mate the ends there The is imemb'e 174/88 C 339/60 C 89 C 90 C91 P 94 one end of a connector housing having a shoulder stop C 126J R E1 therein against which the dielectric sleeve registers so that uponcontinued insertion the dielectric sleeve is [561 firs' rzlizzr iiatzzzsr22:"

- 10118 g ms 0 la c e u a mg UNITED STATES PATENTS sheath. Thedielectric sleeve thus may serve as a posi- 3,343,l22 9/1967 Drogo339/177 R tioner or Stop f use i a i i g so h 3,439,294 4/1969 Flanaganet al.... 339/177 R crimping occurs on the extreme end of the Contact 3161453 12/1964 Powell 339/177 R whereby bending is at a minimum and alsois operative 3,474,391 10/1969 Gartzke et al 339/177 E to positivelylocatethe Contact in a predictably fixed position in the housing whilesimultaneously aligning FOREIGN PATENTS OR APPLICATIONS the samediametrically in spaced relation within a small 785,425 10/1957 GreatBritain 339/177 R bore therein.

2 Claims, 9 Drawing Figures PATENTEU 4975 sumzur SUBMINIATURE COAXIALCONTACT BACKGROUND OF THE INVENTION The present invention relatesgenerally to coaxial cable connectors and more particularly to animproved method and apparatus for connecting subminiature coaxialcables.

Among the problems in meeting the high density requirements of todayselectrical connectors suitable for use in the new rack and panel typesas well as in readily available manually disconnectable connectorhousings is that of providing a satisfactory subminiature shield wire,or coaxial, contact, such as one designed for a size 16 cavity with amated electrical length only slightly over one-half inch. Generally,such contacts heretofore available have been readily subject to bendingduring crimping, which results in extreme difficulty being encounteredin precisely aligning the contact within an encircling small bore in aconnector housing. Further, because of their size, no satisfactorymethod has heretofore been provided for accurately positioning thecontact in a definite axial location within the connector housing.

SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to provide a new and improved coaxial contact for connectingsubminiature cables in high density connectors.

Another object of the present invention is to provide a novel apparatusfor connecting subminiature coaxial cables having a connector housingand a coaxial contact which is readily alignable in spaced relationwithin a small axial bore of the housing.

Still another object of this invention is to provide a novel apparatusfor connecting subminiature coaxial cables having a connector housingand a coaxial contact which is accurately positionable in a fixedlocation within the housing.

Yet another object of this invention is the provision of a connectorhousing and a subminiature coaxial contact which are so cooperativelyconstructed as to facilitate ready disposition of the contact within abore in the housing at a fixed location therein and in axial alignmentin spaced relation with the wall defining the housing bore.

It is a further object of this invention to provide a subminiaturecoaxial contact which is subject to minimum bending during crimping andaccordingly is more readily alignable in spaced relation within asmall-sized encircling bore of a connector housing.

A still further object of this invention is to provide an improvedmethod of connecting subminiature coaxial cables in high densityconnectors.

A yet further object of the present invention is the provision of animproved method of connecting subminiature coaxial cables which insuresalignability and accurate positioning of the cable contact within a boreof a connector housing.

The foregoing and other objects are attained in accordance with oneaspect of the present invention by a subminiature coaxial contact havinga cavity in one end for receiving a stripped center conductor of asmall-size coaxial cable and being provided with a dielectric sleevemovably positioned thereon and initially disposed intermediate the endsthereof. The subminiature contact is insertable into one end of aconnector housing have a shoulder stop therein against which thedielectric sleeve registers so that upon continued inscrtion thedielectric sleeve is caused to slidably traverse the inwardly movingcontact until it is positioned against the end of the insulating sheathdisposed about the unstripped portion of the center conductor'of thecoaxial cable. The dielectric sleeve thus may serve as a positioner orstop for use with a crimping tool prior to inserting the contact intothe connector housing so that crimping occurs on the extreme end of thecontact whereby bending is at a minimum and it is also operative duringinsertion into the connector housing to positively locate the contact ina predictable fixed position therein while simultaneously aligning thesame diametrically in spaced relation within a small bore of theconnector housingzThe subminiature coaxial contact may have a pincontact on the end opposite the center conductor-receiving cavity or asocket contact, so that when used together, the respective connectorhousings of the subminiature pin contact assembly and the subminiaturesocket contact assembly are cooperatively engageable to readily permitthe maintenance of alignment of the pin and socket contacts and toobtain the shortest posssible mating electrical legnth.

BRIEF DESCRIPTION OF THE DRAWINGS Various other objects, features andattendant advantages of the present invention will be more fullyappreciated as the same becomes better understood from the followingdetailed description when considered in connection with the accompanyingdrawings, in which like reference numerals designate like orcorresponding parts throughout the several views, and wherein:

FIG. 1 is a perspective view of a subminiature pin center contact havinga pair of dielectric sleeves positioned thereon and a connector housingfor receiving the contact being formed in accordance with the presentinvention;

FIG. 2 is a longitudinal cross-section of the connector housing and thepin center contact shown in FIG. 1 having a stripped center conductor ofa subminiature coaxial cable secured within the contact and illustratingin part a crimping tool for crimping the one end of the contact;

FIG. 3 is another cross-sectional view of the apparatus of FIG. 1showing the contact being inserted into the connector housing with theone dielectric sleeve registering with a stop therein;

FIG. 4 is another cross-sectional view of the fully assembled apparatusillustrated in FIG. 1;

FIG. 5 is a perspective view of a socket, or female, center contacthaving a movable dielectric sleeve disposed thereon and a connectorhousing for receiving the contact being formed in accordance with thepresent invention;

FIG. 6 is a longitudinal cross-section view of the connector housing andthe socket contact shown in FIG. 5 and illustrating in part a crimpingtool for crimping one end of the socket contact when a center conductorof a subminiature coaxial cable is received therein;

FIG. 7 is a cross-sectional view of the apparatus illustrated in FIG. 5showing the socket contact being inserted into the connector housingwith the dielectric sleeve registering against a stop therein;

FIG. 8 is another cross-sectional view of the apparatus shown in FIG. 5when fully assembled; and

FIG. 9 is a cross-sectional view of the pin contact assembly shown inFIG. 4 and the socket contact assembly shown in FIG. 8 beinginter-engaged for connecting the respective subminiature cables thereof.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to thedrawings, and more particularly to FIGS. 1 and 2 thereof, there is showna male center contact generally indicated by the reference numeral 10being formed with one cylindrical end portion 11 having anaxially-extending cavity 12 therein and another end portion 13 being anelongate pin contact of a smaller diameter than end portion 11 andextending coaxially from the end thereof opposite the cavity 12. Adielectric sleeve 14 is slidably positioned on the end portion 11 of thecontact 10 being initially disposed at the end thereof connected withthe pin contact 13 and another dielectric sleeve 15 is slidablypositioned on the pin contact 13 being initially disposed at the endthereof connected with the end portion 11 so that the dielectric sleeves14 and 15 are initially positioned with respective end faces thereofcontacting one another. The dielectric sleeve 14, as shown, has a largerdiameter than that of dielectric sleeve 15. Preferably the sleeves 14and 15 are constructed of Teflon, although it is to be understood thatother suitable materials may be employed. A screw 16 is shown beingthreadably engaged radially into the end portion 11 of the male contact10 at a longitudinal location thereon which is initially not covered bythe dielectric sleeve 14 for the purpose of permitting a centerconductor of a subminiature coaxial cable to be fixedly secured withinthe cavity 12.

The reference numeral 18 generally designates a connector housing forthe male center contact 10 having stepped bores 19, 20 and 21 coaxiallyformed therein which provide shoulders 22 and 23 at the points of therespective diameter changes. The periphery of the end portion ofconnector housing 18 in which the larger bore 21 is formed has aplurality of rolled V-shaped serrations 24 formed therein, the purposeof which will be set forth hereinbelow. At the other end of theconnector housing 18, an integral tubular portion 25 is provided with aplurality of longitudinal slots 26, preferably being four in numberspaced at 90 intervals, so that the end portion 25 provides a shoulderportion 27 internally thereof at the juncture with the bore 19 andprovides a set of contact springs, the operation of which will bedescribed in greater detail further below.

Still referring to FIG. 2, an engaging wall 28 of a crimping tool 29 isshown positioned about one end of the center contact 10. As is wellknown, it is important to maintain alignment of the inner and outercontacts, especialy in small-size coaxial contacts, and any bendingcaused by crimping of the center contact becomes a critical factor inobtaining such alignment in the dielectric spacer. Thus, in thisembodiment, with the dielectric sleeve 14 being located forwardly on theend portion 11 of contact 10, it acts as a positioner or stop in thecrimping tool, so that the initial location thereof permits the crimp tooccur on the extreme end of the contact. Thus, should any bending actionoccur in the crimp area, the effect is at an absolute minimum ascompared to a crimp centered in the contact length.

Referring now to FIG. 3, the inner, or center, conductor of asubminiature coaxial cable 31 is stripped of its various protective andinsulative jackets and is inserted and fixedly secured within the cavity12 of the center contact 10 by screw member 16. Thereafter, the endportion 11 of the center contact 10 is crimped to the center conductorand the center contact 10 is inserted into the connector housing 18.Upon insertion therein, the dielectric sleeve 14 which snugly fitswithin the bore 21, engages the shoulder 23. At this time, thedielectric sleeve 15 is disposed in the bore 20 of connector housing118. Since the dielectric sleeve 14 is prevented from being furtherdisplaced into the connector housing by its engagement with shoulder 23,further insertion of the center contact 10 into the connector housing 18causes the dielectric sleeve 14 to move to the rear of the end portion11 of the center contact 10 until, as shown in FIG. 4, it is positionedover the previously crimped area and against the facing annular wall 32of the cable insulating sheath 33 at the point to which the same hadbeen previously stripped from the center conductor prior to crimping.Thus, in addition to giving axial alignment on the extreme end of thecontact, the dielectric sleeve 14 also acts as a stop or positioner forthe positive locating of the center contactcable with respect to theconnector housing 18.

Further, the dielectric sleeve 15, during its forced movement throughthe bore portion 20 of the connector housing 18 effected through itsengagement with the annular end of end portion 11, combines with themovable dielectric sleeve 14 being displaced therefrom to providemaximum axial alignment of the center contact 10 within the housing.Movement of the center contact into the connector housing 18 also islimited, of course, as shown in FIG. 4, by the engagement of thedielectric sleeve 15 with the shoulder 22 at the end of bore 20. Thus,the movable dielectric technique permits the shortest possible impedancematch and only requires a double stripping of the cable as opposed tothe conventional triple strip.

The outer braid 34 of the coaxial cable 31 may then be received over theserrated end portion of the connector housing 18 and electricallysecured thereto by a conventional clamping collar 35.

Turning now to FIGS. 5 and 6, a female,-or socket, center contact isgenerally indicated by the reference numeral 441. This female centercontact 411 has an end portion 41 having an elongate cavity 42 thereinfor receiving a center conductor 43 of a coaxial cable which has beenstripped of it various protective and insulative jackets. The other endportion 44 of the female center contact 40 has a slotted socket portion45 on one end which is adapted to receive a corresponding pin contact 13of a male center contact 10. The end portion 44 of the center contact sohas a smaller diameter than the end portion 41 and extends axiallytherefrom. A dielectric sleeve 47 is slidably positioned on the centercontact 40, being initially located at the juncture of the end portions41 and 44. The dielectric sleeve 47 is preferably constructed of Teflonalthough it is to be understood that other suitable materials may beemployed.

The socket portion 45 is designed to offer the maximum frontal openingtarget area, so that instead of a standard slotted and tapered, orpinched tube configuration, the outer surface thereof is kept straightand inward projections 48, shown in FIG. 6, provide the contact area.This gives the maximum bellmouth opening in the front for the bestpossible alignment within the dielectric sleeve 47 and the inwardprojecting surfaces 48 maintain a constant spring length, contactpressure,

as well as consistent location of the electrical contact area.

A connector housing 50 having a bore 51 in one end and a counter bore 52in the other end forming a tapered shoulder 53 therebetween is providedfor receiving the female center contact 40. The periphery of the one endportion of the connector housing 50 in which the counter bore 52 islocated is serrated as indicated by reference numeral 54 in the samemanner as connector housing 18, for the same purpose, being to providegood electrical contact of the outer braid of a coaxial cable whenfastened thereto by a suitable clamping collar. Disposed in the bore 51in the other end of the connector housing 50 is a collar 55 which isadapted to receive the frontal opening target area of the socket portion45 of female center contact 40.

As in the earlier description of the male center contact 10, thestripped center conductor 43 is inserted into the cavity 42 and with thedielectric sleeve 47 serving as a positioner for the crimping tool 29,the end portion 41 of the center contact 40 is crimped about the centerconductor 43. Then, upon insertion of the crimped center contact 40 intothe connector housing 50, the socket portion 45 is positioned in thecollar 55 and the dielectric sleeve 47 engages the shoulder 53, as shownin FIG. 7.

Upon further insertion of the center contact 40 into the connectorhousing 50, the dielectric sleeve 47 is caused to move to the rear ofthe end portion 41 of the center contact 40 until it is positioned overthe previously crimped area and against an end wall 32' of an insulatingsheath 33 of a coaxial cable 31', as shown in FIG. 8. As in the case ofthe male center contact with its dielectric sleeve 14, the dielectricsleeve 47 of the female center contact 40 acts as a stop or positionerfor the center contact-cable location within the connector housing 50,as well as providing axial alignment on the extreme end of the contact.

The outer braid 34' about the insulating sheath 33 of coaxial cable 31is received over the serrated portion 54 of the connector housing 50 andis electrically secured thereto by a clamping collar 35.

Turning now to FIG. 9, an assembled version of the male center contactassembly 10 and the female center contact assembly 40 is shown. Thus,the end portion of the connector housing 50 having the collar 55 thereinis forceably inserted into the set of spring contacts 25 of theconnector housing 18, with the collar 55 slightly projecting from theend of the connector housing 50 being received in the bore 19 ofconnector housing 18 until the end wall of connector housing 50 havingbore 51 therein registers against the shoulder 27. During this forceableinsertion of the end of connector housing 50 into the spring contactarea 25 of connector housing 18, the pin contact 13 of the male centercontact 10 is slidably received between the projections 48 on the innersurfaces of the socket portion 45 of the female center contact 40.

Thus, a novel coaxial cable connection technique is provided whichutilizes a movable dielectric for insuringalignment of the male andfemale contacts and for positively locating these contacts inpredictable fixed positions within their respective connector housings,and thus permits the use of subminiature coaxial cables in high densityconnectors with improved results. Another feature of the invention isthat a dielectric may be fabricated from low cost dielectric tubingwhich is cut to length in order to form the movable and fixed encirclingdielectrics.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is to be understood,therefore, that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described herein.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. A method of terminating coaxial cable, comprising the steps of:

trimming a coaxial cable to expose a predetermined length of a centerconductor thereof from one end of a surrounding insulating sheath;

inserting said center conductor into a forward end portion of a centerconductor contact having a rear end portion of reduced diameter and aslidable dielectric member disposed on the rear end of said forward endportion;

crimping the forward end of said forward end portion of said centerconductor contact against said center conductor;

inserting said crimped center conductor contact and said slidabledielectric member into an electrically conducting connector housing;

receiving said dielectric member against a stop inside said connectorhousing;

further inserting said center conductor contact into said connectorhousing and causing said dielectric member to slidably traverse saidforward end portion of said center conductor contact so as to bedisposed over said crimped forward end of said forward end portion;

stopping said dielectric member against an end of said coaxial cableinsulating sheath; and

crimping the outer braid of said coaxial cable into electrical contactwith the outer periphery of the end of said connector housing receivingsaid center conductor contact.

2. A coaxial connector comprising:

a first elongate center conductor contact having a cavity in one endportion for receiving a center conductor of a coaxial cable and areduced diameter male contact member on the other end portion, said oneend portion being crimpable at one end thereof on said center conductor;

a first dielectric sleeve movably disposed on said first centerconductor contact and initially being positioned at another end of saidone end portion adjacent said male contact member;

a connector housing having means therein for defining a series of atleast three stepped bores of decreasing diameter from a front end ofsaid connector housing for receiving said center conductor contact,thereby forming at least two spaced shoulder stops therein;

said first dielectric sleeve being slidable in the first of said seriesof stepped bores and engageable with the first of said at least twoshoulder stops from said front end of said connector housing uponinsertion of said first center conductor contact therein, and uponfurther insertion being slidably displaced on said one end portion ofsaid first center conductor contact toward the crimpable end thereof;

a second dielectric sleeve disposed on said male contact member of saidfirst center conductor contact being smaller in diameter than said firstdielectric sleeve on said one end portion thereof and further beingslidable in the second of said series of stepped bores and engageablewith the second of said at least two shoulder stops from said front endof said connector housing;

a second elongate center conductor contact having a a second connectorhousing having means for defining at least a pair of stepped bores ofdecreasing diameter from a front end of said second connector housingfor receiving said second center conductor contact, thereby forming atleast one shoulder stop therein;

said third dielectric sleeve upon insertion of said second centerconductor contact into said second connector housing being engageablewith said at least one shoulder stop and upon continued insertion ofsaid second center conductor contact being caused to be displaced onsaid one end portion toward the crimpable end thereof; a collar disposedin the rear bore of said second connector housing and projectingslightly therefrom; spring contact members on the rear end of said firstconnector housing for engagably receiving the rear end of said secondconnector housing with said projecting collar being slidable in therearmost of said series of stepped bores in said first connector housingso as to engage said male contact member in said female contact member;and

stop means in the rear end of said first connector housing for limitingthe insertion therein of said second connector housing.

1. A method of terminating coaxial cable, comprising the steps of:trimming a coaxial cable to expose a predetermined length of a centerconductor thereof from one end of a surrounding insulating sheath;inserting said center conductor into a forward end portion of a centerconductor contact having a rear end portion of reduced diameter and aslidable dielectric member disposed on the rear end of said forward endportion; crimping the forward end of said forward end portion of saidcenter conductor contact against said center conductor; inserting saidcrimped center conductor contact and said slidable dielectric memberinto an electrically conducting connector housing; receiving saiddielectric member agaiNst a stop inside said connector housing; furtherinserting said center conductor contact into said connector housing andcausing said dielectric member to slidably traverse said forward endportion of said center conductor contact so as to be disposed over saidcrimped forward end of said forward end portion; stopping saiddielectric member against an end of said coaxial cable insulatingsheath; and crimping the outer braid of said coaxial cable intoelectrical contact with the outer periphery of the end of said connectorhousing receiving said center conductor contact.
 2. A coaxial connectorcomprising: a first elongate center conductor contact having a cavity inone end portion for receiving a center conductor of a coaxial cable anda reduced diameter male contact member on the other end portion, saidone end portion being crimpable at one end thereof on said centerconductor; a first dielectric sleeve movably disposed on said firstcenter conductor contact and initially being positioned at another endof said one end portion adjacent said male contact member; a connectorhousing having means therein for defining a series of at least threestepped bores of decreasing diameter from a front end of said connectorhousing for receiving said center conductor contact, thereby forming atleast two spaced shoulder stops therein; said first dielectric sleevebeing slidable in the first of said series of stepped bores andengageable with the first of said at least two shoulder stops from saidfront end of said connector housing upon insertion of said first centerconductor contact therein, and upon further insertion being slidablydisplaced on said one end portion of said first center conductor contacttoward the crimpable end thereof; a second dielectric sleeve disposed onsaid male contact member of said first center conductor contact beingsmaller in diameter than said first dielectric sleeve on said one endportion thereof and further being slidable in the second of said seriesof stepped bores and engageable with the second of said at least twoshoulder stops from said front end of said connector housing; a secondelongate center conductor contact having a cavity in one end portion forreceiving a center conductor of another coaxial cable and a reduceddiameter female contact member on the other end portion, said one endportion being crimpable at one end thereof on said center conductor; athird dielectric sleeve movably disposed on said second center conductorcontact and initially being positioned at another end of said one endportion adjacent said female contact member; a second connector housinghaving means for defining at least a pair of stepped bores of decreasingdiameter from a front end of said second connector housing for receivingsaid second center conductor contact, thereby forming at least oneshoulder stop therein; said third dielectric sleeve upon insertion ofsaid second center conductor contact into said second connector housingbeing engageable with said at least one shoulder stop and upon continuedinsertion of said second center conductor contact being caused to bedisplaced on said one end portion toward the crimpable end thereof; acollar disposed in the rear bore of said second connector housing andprojecting slightly therefrom; spring contact members on the rear end ofsaid first connector housing for engagably receiving the rear end ofsaid second connector housing with said projecting collar being slidablein the rearmost of said series of stepped bores in said first connectorhousing so as to engage said male contact member in said female contactmember; and stop means in the rear end of said first connector housingfor limiting the insertion therein of said second connector housing.